#' A precise & pristine [ggplot2] theme with opinionated defaults and an emphasis on typoghraphy
#'
#' You should [import_roboto_condensed()] first and also install the fonts on your
#' system before trying to use this theme.
#'
#' There is an option `hrbrthemes.loadfonts` which -- if set to `TRUE` -- will
#' call `extrafont::loadfonts()` to register non-core fonts with R PDF & PostScript
#' devices. If you are running under Windows, the package calls the same function
#' to register non-core fonts with the Windows graphics device.
#'
#' @md
#' @section Why Roboto Condensed?:
#' It's free, has tolerable kerning pairs and multiple weights. It's also different
#' than Arial Narrow and the fonts most folks use in ggplot2 charts.
#'
#' @md
#' @param base_family,base_size base font family and size
#' @param plot_title_family,plot_title_face,plot_title_size,plot_title_margin plot tilte family, face, size and margin
#' @param subtitle_family,subtitle_face,subtitle_size plot subtitle family, face and size
#' @param subtitle_margin plot subtitle margin bottom (single numeric value)
#' @param strip_text_family,strip_text_face,strip_text_size facet label font family, face and size
#' @param caption_family,caption_face,caption_size,caption_margin plot caption family, face, size and margin
#' @param axis_title_family,axis_title_face,axis_title_size axis title font family, face and size
#' @param axis_title_just axis title font justificationk one of `[blmcrt]`
#' @param axis_text_size font size of axis text
#' @param plot_margin plot margin (specify with [ggplot2::margin])
#' @param panel_spacing panel spacing (use `unit()`)
#' @param grid_col grid color
#' @param grid panel grid (`TRUE`, `FALSE`, or a combination of `X`, `x`, `Y`, `y`)
#' @param axis_col axis color
#' @param axis add x or y axes? `TRUE`, `FALSE`, "`xy`"
#' @param ticks ticks if `TRUE` add ticks
#' @export
#' @examples \dontrun{
#' library(ggplot2)
#' library(dplyr)
#'
#' # seminal scatterplot
#' ggplot(mtcars, aes(mpg, wt)) +
#'   geom_point() +
#'   labs(x="Fuel efficiency (mpg)", y="Weight (tons)",
#'        title="Seminal ggplot2 scatterplot example",
#'        subtitle="A plot that is only useful for demonstration purposes",
#'        caption="Brought to you by the letter 'g'") +
#'   theme_ipsum_rc()
#'
#' # seminal bar chart
#'
#' # note: make this font_rc on Windows
#' update_geom_font_defaults(family=font_rc_light)
#'
#' count(mpg, class) %>%
#'   ggplot(aes(class, n)) +
#'   geom_col() +
#'   geom_text(aes(label=n), nudge_y=3) +
#'   labs(x="Fuel efficiency (mpg)", y="Weight (tons)",
#'        title="Seminal ggplot2 bar chart example",
#'        subtitle="A plot that is only useful for demonstration purposes",
#'        caption="Brought to you by the letter 'g'") +
#'   theme_ipsum_rc(grid="Y") +
#'   theme(axis.text.y=element_blank())
#' }
theme_ipsum_rc <- function(
  base_family="Roboto Condensed", base_size = 11.5,
  plot_title_family=base_family, plot_title_size = 18,
  plot_title_face="bold", plot_title_margin = 10,
  subtitle_family=if (.Platform$OS.type == "windows") "Roboto Condensed" else "Roboto Condensed Light",
  subtitle_size = 13,
  subtitle_face = "plain", subtitle_margin = 15,
  strip_text_family = base_family, strip_text_size = 12,
  strip_text_face = "plain",
  caption_family=if (.Platform$OS.type == "windows") "Roboto Condensed" else "Roboto Condensed Light",
  caption_size = 9,
  caption_face = "plain", caption_margin = 10,
  axis_text_size = base_size,
  axis_title_family = base_family,
  axis_title_size = 9,
  axis_title_face = "plain",
  axis_title_just = "rt",
  plot_margin = margin(30, 30, 30, 30),
  panel_spacing = grid::unit(2, "lines"),
  grid_col = "#cccccc", grid = TRUE,
  axis_col = "#cccccc", axis = FALSE, ticks = FALSE) {

  ret <- ggplot2::theme_minimal(base_family = base_family, base_size = base_size)

  ret <- ret + theme(legend.background = element_blank())
  ret <- ret + theme(legend.key = element_blank())

  ret <- ret + theme(plot.margin = plot_margin)
  ret <- ret + theme(panel.spacing = panel_spacing)

  if (inherits(grid, "character") | grid == TRUE) {
    ret <- ret + theme(panel.grid = element_line(color = grid_col, size = 0.2))
    ret <- ret + theme(panel.grid.major = element_line(color = grid_col, size = 0.2))
    ret <- ret + theme(panel.grid.minor = element_line(color = grid_col, size = 0.15))

    if (inherits(grid, "character")) {
      if (regexpr("X", grid)[1] < 0) ret <- ret + theme(panel.grid.major.x = element_blank())
      if (regexpr("Y", grid)[1] < 0) ret <- ret + theme(panel.grid.major.y = element_blank())
      if (regexpr("x", grid)[1] < 0) ret <- ret + theme(panel.grid.minor.x = element_blank())
      if (regexpr("y", grid)[1] < 0) ret <- ret + theme(panel.grid.minor.y = element_blank())
    }
  } else {
    ret <- ret + theme(panel.grid = element_blank())
    ret <- ret + theme(panel.grid.major  = element_blank())
    ret <- ret + theme(panel.grid.major.x  = element_blank())
    ret <- ret + theme(panel.grid.major.y  = element_blank())
    ret <- ret + theme(panel.grid.minor  = element_blank())
    ret <- ret + theme(panel.grid.minor.x  = element_blank())
    ret <- ret + theme(panel.grid.minor.y  = element_blank())
  }

  if (inherits(axis, "character") | axis == TRUE) {
    ret <- ret + theme(axis.line = element_line(color = axis_col, size = 0.15))
    if (inherits(axis, "character")) {
      axis <- tolower(axis)
      if (regexpr("x", axis)[1] < 0) {
        ret <- ret + theme(axis.line.x = element_blank())
      } else {
        ret <- ret + theme(axis.line.x = element_line(color = axis_col, size = 0.15))
      }
      if (regexpr("y", axis)[1] < 0) {
        ret <- ret + theme(axis.line.y = element_blank())
      } else {
        ret <- ret + theme(axis.line.y = element_line(color = axis_col, size = 0.15))
      }
    } else {
      ret <- ret + theme(axis.line.x = element_line(color = axis_col, size = 0.15))
      ret <- ret + theme(axis.line.y = element_line(color = axis_col, size = 0.15))
    }
  } else {
    ret <- ret + theme(axis.line = element_blank())
  }

  if (!ticks) {
    ret <- ret + theme(axis.ticks = element_blank())
    ret <- ret + theme(axis.ticks.x = element_blank())
    ret <- ret + theme(axis.ticks.y = element_blank())
  } else {
    ret <- ret + theme(axis.ticks = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.x = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.y = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.length = grid::unit(5, "pt"))
  }

  xj <- switch(tolower(substr(axis_title_just, 1, 1)), b = 0, l = 0, m = 0.5, c = 0.5, r = 1, t = 1)
  yj <- switch(tolower(substr(axis_title_just, 2, 2)), b = 0, l = 0, m = 0.5, c = 0.5, r = 1, t = 1)

  ret <- ret + theme(axis.text = element_text(size = axis_text_size, margin = margin(t = 0, r = 0)))
  ret <- ret + theme(axis.text.x = element_text(size = axis_text_size, margin = margin(t = 0)))
  ret <- ret + theme(axis.text.y = element_text(size = axis_text_size, margin = margin(r = 0)))

  ret <- ret + theme(axis.title = element_text(size = axis_title_size, family = axis_title_family))
  ret <- ret + theme(axis.title.x = element_text(
    hjust = xj, size = axis_title_size,
    family = axis_title_family, face = axis_title_face
  ))
  ret <- ret + theme(axis.title.y = element_text(
    hjust = yj, size = axis_title_size,
    family = axis_title_family, face = axis_title_face
  ))
  ret <- ret + theme(axis.title.y.right = element_text(
    hjust = yj, size = axis_title_size, angle = 90,
    family = axis_title_family, face = axis_title_face
  ))

  ret <- ret + theme(strip.text = element_text(
    hjust = 0, size = strip_text_size,
    face = strip_text_face, family = strip_text_family
  ))

  ret <- ret + theme(plot.title = element_text(
    hjust = 0, size = plot_title_size,
    margin = margin(b = plot_title_margin),
    family = plot_title_family, face = plot_title_face
  ))
  ret <- ret + theme(plot.subtitle = element_text(
    hjust = 0, size = subtitle_size,
    margin = margin(b = subtitle_margin),
    family = subtitle_family, face = subtitle_face
  ))
  ret <- ret + theme(plot.caption = element_text(
    hjust = 1, size = caption_size,
    margin = margin(t = caption_margin),
    family = caption_family, face = caption_face
  ))

  ret

}

#' Import Roboto Condensed font for use in charts
#'
#' Roboto Condensed is a trademark of Google.
#'
#' There is an option `hrbrthemes.loadfonts` which -- if set to `TRUE` -- will
#' call `extrafont::loadfonts()` to register non-core fonts with R PDF & PostScript
#' devices. If you are running under Windows, the package calls the same function
#' to register non-core fonts with the Windows graphics device.
#'
#' @md
#' @note This will take care of ensuring PDF/PostScript usage. The location of the
#'   font directory is displayed after the base import is complete. It is highly
#'   recommended that you install them on your system the same way you would any
#'   other font you wish to use in other programs.
#' @export
import_roboto_condensed <- function() {

  rc_font_dir <- system.file("fonts", "roboto-condensed", package="hrbrthemes")

  suppressWarnings(suppressMessages(extrafont::font_import(rc_font_dir, prompt=FALSE)))

  message(
    sprintf(
      "You will likely need to install these fonts on your system as well.\n\nYou can find them in [%s]",
      rc_font_dir)
  )

}

#' @rdname RobotoCondensed
#' @md
#' @title Roboto Condensed font name R variable aliases
#' @description `font_rc` == "`Roboto Condensed`"
#' @format length 1 character vector
#' @export
font_rc <- "Roboto Condensed"

#' @rdname RobotoCondensed
#' @md
#' @note `font_rc_light` (a.k.a. "`Roboto Condensed Light`") is not available on
#'     Windows and will throw a warning if used in plots.
#' @description `font_fc_light` == "`Roboto Condensed Light`"
#' @export
font_rc_light <- "Roboto Condensed Light"

